Pressure regulating valve

ABSTRACT

A pressure regulating valve adapted to be interposed between a pressurized liquid supply whose pressure varies and a spray nozzle or other liquid applicator from which the liquid is discharged. The valve, actuated only when the pressure of the incoming liquid exceeds a predetermined minimum level, functions to maintain the flow of liquid fed to the applicator at a substantially constant pressure level regardless of variations in the pressure of the liquid supply, and to cut off flow automatically should the supply pressure fall below an acceptable level.

BACKGROUND OF INVENTION

1. Field of Invention

This invention relates generally to regulating valves to control fluidflow, and more particularly to a pressure regulating valve supplied witha pressurized liquid whose pressure varies, the valve yielding a liquidhaving a substantially constant pressure level.

2. Status of Prior Art

A regulating valve derives its power of operation from the fluid beingcontrolled and functions to hold constant a fluid quantity, such aspressure or flow velocity. While the invention resides in a regulatingvalve yielding a fluid having a substantially constant pressure and avalve of this type has many practical applications, a valve inaccordance with the invention will be described herein in connectionwith a backpack spraying equipment, for in this context the valve hasparticular value. It is to be understood, however, that the valve is byno means limited to this application.

Suppliers of agricultural chemicals, such as insecticides, herbicidesand fungicides in liquid form, have developed specific guidelines forthe safe and effective use of these chemicals in order to satisfyrequirements mandated by law. Typically, users of backpack sprayingequipment must adjust their system for different product uses. This isdone by installing a nozzle, a spray tip, or wand designed to afford thedesired spray coverage. These nozzles or wands have different orificesizes which when fed liquids at a certain pressure will then allow acalculable flow rate.

Backpack spray systems in current use are capable of producing liquidpressures for use up to 70 PSI. A hand-operated pump mechanism coupledto a small pressure chamber inside the backpack reservoir is used by theoperator to maintain a satisfactory working pressure during applicationsof the liquid. Though this arrangement allows a user to quickly reach anacceptable working pressure and to begin spraying, it demands frequentpumping, and this gives rise to varying pressures.

Since flow rate is a function of both liquid pressure and the size ofthe orifice through which the liquid is discharged, backpack spraysystems currently in use inherently produce varying flow rates. As aconsequence, the user of the system has little control over the deliveryof the chemicals being sprayed, and an excessive or an inadequateapplication of the chemicals is then difficult to avoid.

Many backpack spraying systems in current use are provided with a wandhaving a shut off valve, the wand being coupled to the liquid chemicalreservoir in the backpack which includes a hand-operated pump mechanism.Should the operator open the spray wand valve before the system has beenpumped to a satisfactory working pressure, the liquid will not then besprayed out of the wand, but will instead drip, dribble or leak out ofthe wand and be deposited anywhere but on its intended target. Thereason for this leakage is that when liquid is fed to a spray nozzle, itwill only atomize and emerge as a spray when the pressure of the liquidis at a relatively high level. Should the pressure fall below thislevel, it will simply leak out of the nozzle.

This leakage of chemicals is not only wasteful, but it may also behazardous if the leaked liquids make contact with the operator's skin orclothing. Such leakage can also occur if during a spraying operation theliquid pressure drops below a level at which the liquid atomizes.

SUMMARY OF INVENTION

In view of the foregoing, the main object of the invention is to providea pressure regulating valve adapted to be interposed between apressurized liquid supply whose pressure is unregulated and thereforevaries, and a spray nozzle or other liquid applicator from which theliquid is discharged, the valve functioning to maintain at asubstantially constant level the pressure of liquid fed to theapplicator regardless of variations in the supply liquid pressure.

A significant feature of a regulating valve in accordance with theinvention is that it acts automatically to cut off flow when the levelof pressure of the liquid supplied thereto falls below an acceptableminimum value. Thus when the valve is interposed in a backpack sprayingsystem and the liquid pressure of the liquid in the backpack reservoirfalls below a level sufficient to effect spraying, the flow of liquid isinterrupted until such time as the liquid pressure rises above theminimum level.

Briefly stated, these objects are accomplished by a pressure regulatingvalve adapted to be interposed between a pressurized liquid supply whosepressure varies and a spray nozzle or other liquid applicator from whichthe liquid is discharged, the valve functioning to maintain the flow ofliquid fed to the applicator at a substantially constant pressure levelregardless of variations in the pressure of the liquid and to cut offflow automatically should this pressure fall below an acceptable level.

The regulating valve includes an input section whose inlet is coupled tothe supply of pressurized liquid, the input section having a barrierwall at its end provided with a central port. And included is an outputsection having an outlet coupled to the applicator. Interposed betweenthe input and output sections is a diaphragm chamber which regulatesliquid flow between the sections. This chamber includes a spring-biasedpiston that normally urges a diaphragm against the outer surface of thebarrier wall.

Anchored on the piston is a stem that projects through the port into theinput section and is coaxial therewith to define a flow passage. Thestem terminates in an inverted conical throttle head which defines anorifice whose size depends on the distance between the inner surface ofthe head and the inner surface of the barrier wall, the orifice passingliquid into the port flow passage.

When liquid pressure in the input section is sufficient to actuate thevalve by overcoming the spring pressure urging the diaphragm against theouter surface of the barrier wall, the diaphragm is then displaced fromthe wall to permit liquid to flow from the orifice through the flowpassage into the diaphragm chamber and from there into the outputsection to be discharged therefrom. The displacement of the diaphragm isa function of the liquid pressure in the input section and results in acorresponding displacement of the throttle head, thereby reducing thesize of the orifice to lower the pressure of the liquid in the diaphragmchamber.

As a consequence, when the valve is actuated and the pressure of liquidsupplied to the input section varies, the size of the orifice feedingthis liquid into the flow passage leading into the diaphragm chamber ismodulated to maintain the liquid in the chamber at a substantiallyconstant pressure level.

BRIEF DESCRIPTION OF DRAWINGS

For a better understanding of the invention, as well as other objectsthereof, reference is made to the following detailed description to beread in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view of a pressure regulating valve inaccordance with the invention;

FIG. 2 is a longitudinal section taken through the valve whichillustrates the internal structure of the valve and its operation whenthe pressurized liquid supplied thereto has a pressure insufficient toactuate the valve; and

FIG. 3 is a section taken through the valve when the input liquidpressure is at a level sufficient to actuate the valve to cause liquidto be discharged from its outlet at a substantially constant pressurelevel.

DESCRIPTION OF THE INVENTION

The Regulating Valve Structure:

FIG. 1 illustrates a regulating valve in accordance with the invention,generally identified by reference numeral 10. Valve 10 is interposedbetween a source 11 of pressurized liquid whose pressure varies, and aspray nozzle 12 or other liquid applicator from which the liquid isdischarged.

Valve 10, which is actuated only when the pressure of the incomingliquid exceeds a predetermined minimum level, function to maintain theflow of liquid fed to spray nozzle at a substantially constant pressurelevel regardless of variations in the pressure of liquid supplied to thevalve and to cut off flow automatically should the supply pressure fallbelow an acceptable level.

In the case of backpack spraying equipment in which a chemical issprayed on crops, a regulating valve 10 in accordance with the inventionwill automatically cut off liquid when the liquid pressure isinsufficient to atomize the liquid to produce a spray; hence the valvewill avoid leakage of the liquid from the valve. And when the pressureof the liquid is above the minimum level at which atomization takesplace, valve 10 will then regulate the flow of liquid fed to the spraynozzle to maintain a substantially constant pressure despite variationsin supply liquid pressure. Consequently the user of the valve-regulatedsystem is able to apply a proper volume of the agricultural liquidchemical to the crops being sprayed and to avoid an excessive or aninadequate application of the liquid.

As shown in FIG. 2, regulating valve includes an input section IS whosetubular inlet is coupled to a backpack or other liquid supply whosepressure varies. The input section is provided at its end and with abarrier wall 13 having a central port P therein. The valve also includesan output section OS whose outlet is coupled to a spray nozzle or otherliquid applicator.

Interposed between input section IS and output section OS is a diaphragmchamber DC which regulates the flow of liquid from the input to theoutput section. The valve is provided with a housing forme ofcylindrical components 14 and 15 clamped together by an internallythreaded collar 16.

Disposed within diaphragm chamber DC is a cylindrical shell 17 supportedon barrier wall 13, the shell being concentric with port P. Mounted onshell 17 is a flexible diaphragm 18 having a flat face parallel to theouter surface of barrier wall 13. Engaging the flat surface of diaphragm16 is the nose of a hollow piston 19 which is slidable on a post 20anchored on the base 21 of a cylindrical frame F. Frame F is supportedon shell 17 coaxially within the diaphragm chamber DC.

Interposed between a shoulder on piston 19 and base 21 is a compressiblehelical spring 22 that acts to urge the flat face of diaphragm 18against a raised ring 13' which projects into the diaphragm chamber DCfrom the outer surface of barrier wall 13. Anchored on the nose ofpiston 19 and projecting through port P into input section IS is a stem23. Stem 23 is coaxial with port P to define an annular flow passageconnecting the input section to the diaphragm chamber DC. Stem 23terminates in a throttle head 24 having an inverted conical form whoseinner surface is spaced from the inner surface of barrier wall 13 todefine an annular orifice O that leads into the flow passage. The sizeof orifice O depends on the distance between head 24 form and barrierwall 13. The diaphragm 18 and piston 19 thus comprise a diaphragmassembly connected to the throttle head 24 by stem 23 to thereby providean adjustable modulating unit. When the modulating unit is biased byspring 22 into a closed position as shown in FIG. 2, the flat face ofthe diaphragm 18 is pressed against the raised ring 13' to therebydefine a pressure chamber PC which is open to the input section 15 viathe flow passage through the barrier wall 13, and closed to thediaphragm chamber DC.

Cylindrical frame F is joined to shell 17 to form an internal cavitywhich houses the spring-biased piston, the cavity being vented to theatmosphere through a vent hole 25.

As indicated by the arrows in FIG. 3, when the flat face of thediaphragm is displaced away from the raised ring 13' on the barrier wall13, liquid then flows through openings in shell 17 into the annularspace between frame F and the casing of the valve, and from there intothe free space between base 21 of the frame and the entry to the outletsection OS, the liquid then passing through the outlet section fromwhich it is discharged.

Operation:

FIG. 2 illustrates the state of valve 10 when the pressure of theincoming liquid from the supply is insufficient to actuate the valve. Inthat state, the flat face of diaphragm 18 is pressed by the springbiased piston 19 against the raised ring 131 on the outer surface of thebarrier wall 13 to block the flow passage in port P. Hence when thepressure of the liquid from the source is at a predetermined minimumlevel below that necessary to overcome the force of the spring 22, flowto the spray nozzle is cut off.

When, however, the supply liquid pressure acting on the throttle head 24in the input section and on the flat face of the diaphragm within theconfines of the pressure chamber PC is at a level sufficient to overcomethe spring force, then as shown in FIG. 3, the flat face of diaphragm 18is displaced from the raised ring 13' projecting from the barrier wallso that now the liquid can flow from the input section IS through theflow passage in port P into diaphragm chamber DC.

The degree to which the piston engaging the flat face of the diaphragmis displaced away from the outer surface of barrier wall 13 depends onthe pressure of liquid in input section IS. The higher the pressure, thegreater the piston displacement and the greater the degree to whichthrottle head 24 is brought closer to the inner surface of barrier wall13. The closer the head is to the barrier wall, the smaller is the sizeof orifice O which admits liquid into the port flow passage.

Hence the size of orifice O and the rate of liquid flow therethrough ismodulated as an inverse function of the pressure of liquid in the inputsection, the higher the pressure, the smaller the orifice size. By somodulating the orifice size and liquid flow rate, for any given nozzlesize the pressure of liquid fed into diaphragm chamber DC is maintainedat a substantially constant pressure level regardless of the varyingpressure of liquid in the input section IS, but only as long as thispressure is at a level sufficient to actuate the valve.

If, for example, an input section liquid pressure of 30 PSI issufficient to actuate the valve, as this pressure then varies from 30 to70 PSI, the pressure in the diaphragm chamber will be maintained atabout 32 PSI so that the pressure of liquid discharged from the outputsection and fed to an applicator will be maintained at a substantiallyconstant pressure level. But should the pressure of liquid fed into thevalve fall below an acceptable level, the valve will automatically cutoff and remain in this state until the pressure of liquid suppliedthereto exceeds a predetermined minimal level.

While there has been shown a preferred embodiment of a pressureregulating valve in accordance with the invention, it will beappreciated that many changes may be made therein without departing fromthe spirit of the invention.

I claim:
 1. A regulating valve adapted to be interposed between apressurized fluid supply whose pressure varies and a fluid applicatorfrom which the fluid is discharged, the valve when actuated functioningto maintain the pressure of fluid fed to the applicator at asubstantially constant level regardless of variations in the pressure ofsaid fluid supply, said valve comprising:A. an input section having aninlet coupled to said supply, and having at its end a barrier wallprovided with a central port, and an output section having an outletcoupled to said applicator; B. a diaphragm chamber interposed betweensaid input section and said output section; and C. modulating meansincluding a diaphragm in said diaphragm chamber for modulating the sizeof said port as an inverse function of the varying pressure of the fluidin said input section whereby the pressure of the fluid in the diaphragmchamber is maintained at a substantially constant level, said valvebeing automatically actuated when the varying pressure of fluid in saidinput section exceeds a predetermined minimum level, and beingautomatically closed when said varying pressure is insufficient toachieve valve actuation.
 2. A valve as set forth in claim 1, in whichsaid diaphragm is normally urged against an outer surface of the barrierwall by a spring-biased piston.
 3. A valve as set forth in claim 2, inwhich said diaphragm is mounted on a shell support on said barrier wall.4. A valve as set forth in claim 3, in which a stem is anchored on thepiston and projects through said port into the input chamber, the stembeing coaxial with the port to define a flow passage between the inputsection and the diaphragm.
 5. A valve as set forth in claim 4, in whichthe stem terminates in a throttle head that defines with an innersurface of the barrier wall an orifice leading into said flow passage.6. A valve as set forth in claim 5, in which the head has an invertedconical form whose inner surface is spaced from the inner surface of thebarrier wall.
 7. A valve as set forth in claim 6, in which the pressureapplied to said piston by said spring is such that when the pressure ofthe fluid in the input section overcomes the spring pressure to displacethe diaphragm, the size of the orifice is then modulated as a functionof the fluid pressure.
 8. A valve as set forth in claim 7, in which saidpiston is slidable on a post anchored on the base of a frame supportedon said shell.
 9. A valve as set forth in claim 8, in which said springis interposed between a shoulder on said piston and the base of theframe.
 10. A valve as set forth in claim 9, provided with a cylindricalcasing concentric with said frame.
 11. A regulating valve adapted to beinterposed between a pressurized fluid supply whose pressure varies anda fluid applicator from which the fluid is discharged, the valve whenactuated functioning to maintain the pressure of fluid fed to theapplicator at a substantially constant level, said valve comprising:A. ahousing having an input section adapted to be connected to saidpressurized fluid supply, an outlet section adapted to be connected tosaid applicator, and a diaphragm chamber interposed between said inputand output sections, said diaphragm chamber being in communication withsaid output section and being separated from said input section by abarrier wall having a port extending therethrough; and B. a modulatingunit including a diaphragm assembly in said diaphragm chamber connectedto throttle head in said input section by a stem, said stem extendingthrough and cooperating with said port to define a flow passage and saidthrottle head coacting in spaced relationship with said barrier wall todefine an orifice leading to said flow passage, said modulating unitbeing movably responsive to variations in the pressure of the fluidbeing supplied to said input section to maintain the pressure of thefluid being delivered to said applicator via said flow passage,diaphragm chamber and output section at a substantially constant levelby varying the size of said orifice as an inverse function of the fluidpressure in said input section, said valve being automatically openedwhen the varying pressure of the fluid being supplied to said inputsection exceeds a predetermined minimum level, and being automaticallyclosed when said varying pressure is insufficient to achieve valveactuation.
 12. The regulating valve as claim in claim 11 wherein saidbarrier wall has a ring surrounding said opening and protruding intosaid diaphragm chamber, and spring means for resiliently urging saidmodulating unit into a closed position at which said diaphragm assemblyis pressed against said ring to cooperate therewith in defining apressure chamber open to said input section via said flow passage andclosed to said diaphragm chamber.
 13. The regulating valve as claimed inclaim 12 wherein said valve is opened by fluid pressure acting on saidthrottle head in said input section and on said diaphragm assemblywithin said pressure chamber.
 14. A regulating valve adapted to beinterposed between a pressurized fluid supply whose pressure varies anda fluid applicator from which the fluid is discharged, the valve whenactuated functioning to maintain the pressure of fluid fed to theapplicator at a substantially constant level, said valve comprising:A. ahousing having an input section adapted to be connected to saidpressurized fluid supply, an outlet section adapted to be connected tosaid applicator, and a diaphragm chamber interposed between said inputand output sections, said diaphragm chamber being in communication withsaid output section and being separated from said input section by abarrier wall having a port extending therethrough, said barrier wallhaving a ring thereon surrounding said port and protruding from saidbarrier wall into said diaphragm chamber; B. a modulating unit includinga diaphragm assembly in said diaphragm chamber connected to throttlehead in said input section by a stem, said stem extending through andcooperating with said port to define a flow passage and said throttlehead coacting in spaced relationship with said barrier wall to define anorifice leading to said flow passage; and C. spring means forresiliently urging said modulating unit into a closed position at whichsaid diaphragm assembly is pressed against said ring to cooperatetherewith in defining a pressure chamber open to said input section viasaid flow passage and closed to said diaphragm chamber, said modulatingunit being shiftable from said closed position to an open position inresponse to fluid pressure above a predetermined level in said pressurechamber and being movable when in said open position in response tovariations in the pressure of the fluid acting on said diaphragmassembly to vary the size of said orifice in a manner such as tomaintain the pressure of the fluid being delivered to said applicatorvia said flow passage, diaphragm chamber and output section at asubstantially constant level.